① 500 mL, respectively placed in a beaker dyeing wastewater mixing speed: 120 r/min, adding a certain amount of bleaching agent and PAC, stir 2 min after adding coagulant PAM, stirring for 3 min, rest for layering, take supernatant was measured. Reaction at room temperature.
② separate dyes into quality concentration of aqueous solution of 100 mg/l, model 721 spectrophotometer determination of maximum absorption wavelength of the dye on, respectively, as the photoelectric Colorimetry wavelength.
③ colour test: a single determination of dyes using spectrophotometry and determination of mixed dye dilution method.
Black-decoloration rate calculation
The decolorization rate R%= (1-A/A. ) X100%
In the formula: absorbance of A--;
A。 --Former absorbance.
II determination of chemical oxygen demand by potassium dichromate method .